1. What’s the difference between null and undefined?

Null: Null means nothing. Null used to define that something is programmatically empty. The programmer used it intentionally to refer that there has no value. For example:

const myObj = {name: 'John', age: null}

Undefined: we can get undefined many ways like:

2. What’s the difference between double equal (==) and triple equal (===)?

If someone asks you that question. The simple answer…


In this article, I wanna discuss 10 important things about react. You know react is the most popular open-source JavaScript library which use to build UI (user interface) easily. So without wasting any more time let’s start…

1. React is all about components.

In react, everything is a component. You can re-use a code through react component. That means you can use a component much more time like the below example. Where we use the Blog component three times.


All you know that ES6 ( ECMAScript ) is the second major version of JavaScript. It was released in 2015. Now I wanna discuss some important concepts about ES6.

JavaScript Hoisting

In JavaScript, a variable can be used before it’s declared. If we declare a variable with the var keyword it was hoisted to the top and var is the global scope. Hoisting is JavaScript default behavior it’s hoisted all variables to the top.


This method used for concatenates a string with another string and return a new string.

Gazi Robiul Alam Sagor

Front-End Developer || MERN Stack Developer

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